1. Field of the Invention
The present invention relates to improvements of a computer wherein processing of input numeric data may be much facilitated.
2. Description of the Prior Art
The sequence of a date data or the sequence of a numeric data representing a year, a numeric data representing a month and a numeric data representing a day to be input to a computer is different from one country to another. For instance, in Japan the sequence is
The year in Showa era, the month and the day or PA1 The year in Christian era, the month and the day. PA1 The day, the month and the year in Christian era.
In United States and European countries, the sequence is in general
The month, the day and the year in Christian era, but in England the sequence is
In general, with the conventional desktop computers capable of computing days and recording the date for accounting purpose, one of the above four sequences is selected and the date data must be entered in the predetermined sequence. Therefore the computers with one date input sequence are very convenient for those in one country but are inconvenient to those in other countries. In Japan the date data input sequence is different from one office to another and in some offices Japanese date system is employed; in some offices European system or England system or both; and in some offices both the Showa era and Christian era are used. Therefore the computers with only one date data entry system are very inconvenient to those living in a country where a data is represented in four different sequences.
The conventional computers for accounting have been in general designed for solving only simple routines not for solving complex accounting problems in the banking, real estate business and the like. As a result, the mathematical tables have been widely used in order to solve the problems involving compound interest, annuity, depreciation and the like, but the mathematical tables generally do not provide all answers for all problems. In addition, the accuracy of the result obtained with the aid of the mathematical tables is greatly dependent upon the accuracy of the mathematical tables themselves and the approximation by an interpolation method used. Furthermore, without the knowledge of the mathematical tables they cannot be used at all. In other words, a training is needed before one can use them.
A calculator which is similar to those disclosed in this specification is disclosed in for instance U.S. Pat. No. 3,863,060, but its keying system is very complex so that without an adequate training no one can use it in a very efficient manner.
In accounting the obtained results must be rounded, raised or truncated or chopped. To solve this problem there has been invented and demonstrated an electronic microcomputer wherein indicator means is provided for specifying a digit position lower than the decimal point so that the digits below the specified digit position may be rounded, raised or truncated or chopped. However there arises a problem when the digits below a specified digit position higher than the decimal point must be rounded, raised or chopped. Assume that the digits lower than the N-th digit position higher than the decimal point be required to be rounded. First the first digit position lower than the decimal point must be indicated by the indication means, and the numeric data is divided by 10.sup.N. Thereafter a quotient must be multiplied by 10.sup.N. Thus the operation is very complex.